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I 32 JOSEPH B. HUNN AND ROSALIE A. SCHNICK kill, the number of species involved, agency protocol, instructions from the analytical facility, and the estimated costs of analyses. Water Samples After tests of water quality characteristics, such as dissolved oxygen, pH, conductivity, salinity, and temperature, have been completed, grab samples of water should be taken. (For information on the type of container needed, sample size, and methods of preservation, see Table 4.5.) At a minimum, samples should be collected above, within, and below the kill area (Figs. 4.1 and 4.2). The specific types of sam- pling and analyses to be run must be determined on a case-by-case basis by the on-site investigator. Before the sample bottles are filled, each bottle should be rinsed two or three times with the water that is being sampled (unless the bottle contains a preservative or dechlorinating agent). Water sam- ples must be refrigerated at 4° C in amber bottles and stored in darkness (Table 4.5). The number of samples to be taken and sampling methods should be determined by consultation with the agency that is to perform the analyses (Keith et al. 1983). If no guidance is available, as many samples as convenient should be taken over the area. Although it may not be necessary to have all samples analyzed, there may not be another opportunity to collect useful samples. Sampling protocols should be in place, if possible, before investigative sampling is begun. For further information, see Hill (1983), Keith et al. (1983), and APHA et al. (1985). The minimum volume needed for water samples varies with the type of analysis to be performed on the sample. In general, a 1-liter sample is sufficient. It is important that properly cleaned, prepared con- tainers be used to collect and store the samples. In general, samples to be analyzed for inorganic com- pounds can be taken with plastic (polyethylene or equivalent) bottles that have been acid washed and rinsed with distilled water. For preservation, sam- ples taken for metals analysis should be acidified to pH 2 with redistilled nitric acid. Samples taken for suspected pesticides or other toxic organics will re- quire glass bottles with Teflon-lined caps. The glass bottles should have been rinsed with hexane and dried before use. If volatile organics are suspected, the sample bottles should be filled to overflowing and capped, leaving no air space. Recommended methods of preservation and storage times are given in Table 4.5. Properly cleaned and stored sample bottles and preservatives should be part of the fish kill investigation kit (see Chapter 12); such con- tainers are commercially available. Ampules that contain premeasured amounts of acid for preserva- Small, baited traps can be used to collect surviving forage fish from the site of a fish kill or from a control area.